DuPont Chairman and CEO Ellen Kullman was tight-lipped Tuesday on CNBC about Nelson Peltz's investment in the company—saying she has not spoken with the activist investor.

"We love all our investors," joked Kullman, who was interviewed on "Squawk Box" shortly after DuPont reported better-than-expected earnings and announced that it's looking to sell or spin off its often-volatile performance chemicals business.

"Since 2009, we've been working on the transformation of DuPont," she said. And as that continues, "we've been looking at the alternatives for our performance chemicals segment for a few months."

"The power of biotechnology and enzymes to really change the face of modern materials is where we're going."

At last week's Delivering Alpha Conference, presented by CNBC and Institutional Investor, it was revealed that Peltz, co-founder of Trian Fund Management, has bought up a large chunk of DuPont stock.

While Peltz declined comment, BGC Partners chemicals analyst Mark Gulley told "Squawk Box" on Tuesday he thought Peltz might be interested in proposing the company separate into two pieces, with the agriculture, nutrition, and biotech businesses going one way and industrial chemicals going the other way. The strategic review of performance chemicals is "certainly a step in the right direction," Gulley added.

DuPont's performance chemicals segment generated sales of $7.2 billion in 2012, or 20 percent of total sales. The company's titanium dioxide paint business (TiO2)—which is part of that unit—is the world's largest, and its sales are considered a barometer of broader economic health.

"The TiO2 business has been a real issue for investors given the volatility and the cyclicality," Gulley said. "It went from peak to trough in about 12 months," starting in last year's second quarter.

As for overall second-quarter profits, the company said Tuesday it earned a $1.28 a share on revenue of $9.84 billion. Wall Street analysts had expected per-share earnings of a $1.27 on $10.01 billion in revenue. DuPont also continues to expect full-year earnings of about $3.85 a share, which would be modestly above 2012 results.

"Agriculture is still strong globally," Kullman told CNBC. "Construction [is] obviously a bright spot for the United States. Even in China, we're seeing construction-related industries to be a little stronger."

But looking at autos, she said it's country-by-country. "China has had great volume growth. [The] United States has had great volume growth, [but] we see contraction in other markets like Japan, India and Western Europe."

Kullman acknowledged that uncertainty prevails in the U.S. economy, but said she continues to expect "slow, sequential improvement."

DuPont seeks to exit paint business

DuPont (DD.N) is exploring the sale of its once-lucrative performance chemicals unit, turning its back on the unpredictable paint business to focus on its thriving food and agriculture products.

The largest U.S. chemical maker by market value said it would also consider spinning off the unit, which contributed a fifth of the company's total sales last year and makes the paint pigments used in sunscreen and car paint.

The global titanium dioxide industry, with Dupont, Saudi Arabia's Cristal Global, Tronox, and Huntsman as the largest players, has been in turmoil in recent years.

DuPont's performance chemicals unit, of which paints pigments are a big part, generated total sales of $7.2 billion in 2012. Revenue within the unit fell 8 percent last year.

Some investors have blamed the business for weighing on DuPont's shares, which trade at a discount to those of another rival in the agriculture business, Monsanto.

CNBC reported last week that Trian Fund Management, headed by investor Nelson Peltz, had amassed a "big stake" in DuPont, prompting several analysts to say he might be the push for the company to exit the paint pigment business.

Pesticides beat pigments

Wilmington, Del.-based DuPont, a 211-year-old company, sold its car paint unit for $5 billion last year and bought nutritional supplements maker Danisco for $6 billion in 2011.

The company said on Tuesday it was restructuring its management team to tap the agriculture and nutrition markets, as well as industrial biosciences and advanced materials.

Sales of pesticides and other agricultural products helped DuPont's quarterly profit to scrape past analysts' estimates, as paint pigments once again lagged. Net income fell 13 percent to $1.03 billion in the second quarter.

Kullman said she expected earnings in the second half of the year to be "significantly better" than last year's second half, due to agricultural growth in Latin America and a strong start to the North American planting season.

DuPont also said it expected "modestly" higher full-year earnings as it overcomes steep declines in the titanium dioxide market and weak economic conditions in Europe and parts of Asia.

The company said agriculture sales rose 7 percent in the second quarter, while sales in the performance chemicals business fell 9 percent.

DuPont's shares closed at $57.17 on Monday on the New York Stock Exchange. They have risen about 20 percent in the last six months.